U.S. patent application number 14/310824 was filed with the patent office on 2015-12-24 for integrated circuit chip tester with an anti-rotation link.
The applicant listed for this patent is Titan Semiconductor Tool, LLC. Invention is credited to Victor Landa.
Application Number | 20150372407 14/310824 |
Document ID | / |
Family ID | 54870495 |
Filed Date | 2015-12-24 |
United States Patent
Application |
20150372407 |
Kind Code |
A1 |
Landa; Victor |
December 24, 2015 |
INTEGRATED CIRCUIT CHIP TESTER WITH AN ANTI-ROTATION LINK
Abstract
A socket for testing or connecting an integrated circuit is
disclosed having a platform for receiving the integrated circuit
and adapted to overlay a piece of test equipment or other board,
the platform formed with an array of slots each locating a portion
of a two-piece connector assembly. When the integrated circuit is
seated on the platform, the two piece connector assemblies pivot so
as to make contact between a contact pad on the IC and the board
for establishing or evaluating signal transmission by the IC. The
platform houses a resilient elongate elastomer that biases the
connector assembly out of the platform to make contact with the
board or test equipment. When the IC is placed on the platform, the
bias of the resilient tubular member is overcome and an electrical
connection is established across the connector assembly.
Inventors: |
Landa; Victor; (Ladera
Ranch, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Titan Semiconductor Tool, LLC |
Ladera Ranch |
CA |
US |
|
|
Family ID: |
54870495 |
Appl. No.: |
14/310824 |
Filed: |
June 20, 2014 |
Current U.S.
Class: |
439/376 |
Current CPC
Class: |
H01R 13/22 20130101;
H01R 12/85 20130101; H01R 12/7076 20130101; H01R 12/7005 20130101;
H01R 12/88 20130101; G01R 1/0466 20130101 |
International
Class: |
H01R 12/85 20060101
H01R012/85; H01R 13/22 20060101 H01R013/22; H01R 12/70 20060101
H01R012/70 |
Claims
1. A socket for electrically coupling an integrated circuit (IC) to
a board so that a signal may be transmitted thereto, comprising: a
platform for receiving the integrated circuit thereon; a plurality
of two-piece connector assemblies, each connector assembly
comprising a mount and an associated link pivotable about the
mount; each mount retained in the platform and comprising a curved
cavity on a lateral side opposite an associated link member; each
link member including an arcuate contact surface on an upper side
and extending above the platform, said link adapted for rolling
contact with the integrated circuit, and a rocker arm with a
rounded end seated in the curved cavity of the mount; an elongate
elastomer seated below the plurality of link members having a first
stage compression response and a second stage compression response;
wherein contact between the integrated circuit and the platform
pivots the link against a biasing of the elongate elastomer through
the first stage compression response to the second stage
compression response.
2. The socket of claim 4, wherein the elongate elastomer is square
shaped and seated in a wedge shaped support.
3. The socket of claim 2, wherein the elongate elastomer has a
rounded upper corner extending from the wedge shaped support.
4. A socket for electrically coupling an integrated circuit (IC) to
a board so that a signal may be transmitted thereto, comprising: a
platform for receiving the integrated circuit thereon; a plurality
of two-piece connector assemblies, each connector assembly
comprising a mount and an associated link pivotable about the
mount; each mount retained in the platform and comprising a curved
cavity on a lateral side opposite an associated link member; each
link member including an arcuate contact surface on an upper side
and extending above the platform, said link adapted for rolling
contact with the integrated circuit, and a rocker arm with a
rounded end seated in the curved cavity of the mount; an elongate
elastomer seated below the plurality of link members having a first
stage compression response and a second stage compression response;
wherein contact between the integrated circuit and the platform
pivots the link against a biasing of the elongate elastomer through
the first stage compression response to the second stage
compression response, wherein the first and second stage
compression responses are established by a hole in the elongate
elastomer.
5. The socket of claim 4, wherein the platform includes an angled
side wall that engages an angled opposed surface of the mount to
capture the mount in the platform.
Description
BACKGROUND
[0001] The present invention relates to a socket that electrically
connects an integrated circuit with an IC board. More particularly,
the present invention is directed to a socket, such as those used
for testing or connecting an integrated circuit, that incorporates
an array of two-piece connectors that achieve a positive connection
between an IC device under test (DUT) and a board, such as a load
board of a piece of test equipment or other fixture.
[0002] Integrated circuit tester devices have long been used in the
semiconductor industry to test and evaluate the quality of the
chips off the manufacturing line. Signal integrity is a critical
aspect of chip design and testing. To this end, it is desirable to
maintain impedance through a conducting portion of a contact
interconnecting the integrated circuit lead to its corresponding
load board pad at a particular desired level. The effective
impedance of the design is a function of a number of factors. These
include width and length of conduction path, material of which the
conductive structure is made, material thickness, etc.
[0003] When testing the electrical characteristics of a packaged or
molded semiconductor device such as an integrated circuit (IC), it
is common to utilize a specialized test socket that secures and
connects the IC to the equipment that evaluates its performance,
i.e. a load board. Many different test sockets have been devised
for quickly and temporarily connecting integrated circuit leads of
a chip to be tested to a load board of a tester. Automated test
apparatus in particular use a number of such sockets. Typical
socket arrangements use force brought to bear upon a contact
positioned between a lead of the IC and the load board to deform a
probe tip of the contact and engage a pad on the load board. Such a
configuration provides for positive connection between the pins or
contact pads of the DUT and corresponding leads of a test
apparatus. Examples of this type of connection can be found, for
example, in U.S. Pat. No. 6,409,521 to Rathburn, and U.S. Pat. No.
7,737,708 to Sherry, the teachings and contents of both of which
are fully incorporated herein by reference.
[0004] Whether it is for testing integrated circuits or for
mounting such circuits on a board, appropriate socket-like
connectors are needed. Factors such as cost, having a low profile,
and shortening the electrical signal path drive the industry to
constantly seek to improve on the prior art sockets. A solution to
the foregoing was provided by U.S. Pat. No. 7,918,669 to Tiengtum,
and assigned to the present assignee, the contents of which are
fully incorporated herein by reference. A feature of that device
was a cylindrical elastomer that provided a resilient biasing of
the connectors, which allowed the testing device to reliably make
effective contact with the device under test (DUT). This
cylindrical elastomer, however, wears quickly and begins to deform
after multiple uses, reducing its effectiveness. Once it begins to
wear, it can twist, which leads to further wear and loss of
resiliency. This leads to an issue with the connector establishing
reliable contact under certain conditions. The present invention
addresses those issues.
SUMMARY OF THE INVENTION
[0005] The present invention is a socket for an integrated circuit
having a series of contact pads or other electrical connection
sites linearly arranged preferably along at least one peripheral
edge, the socket including a platform that supports the IC and
houses a plurality of connectors that when engaged with the
integrated circuit's contact pads, complete an electrical
connection between the contact pads and the associated fixture's
contacts below the platform. The socket's platform may have a
plurality of generally parallel slots for aligning and receiving a
corresponding plurality of electrical contacts, one in each slot.
Each electrical contact path is formed of a two piece linkage that
cooperates to form an electrical connection between the contact pad
and the fixture's contact. The two pieces of the contact cooperate
together to form a reliable electrical connection between the IC
and the board.
[0006] The two piece connector assembly is arranged to pivot into
an engaged position without deformation of the elements.
Deformation is advantageously avoided because components that
deform can lose their resiliency and lead to diminished contact or
failure of the socket with repeated life cycles. In the present
invention, a first piece of the contact is referred to as a "mount"
and has generally planar, parallel upper and lower surfaces and a
side surface formed with a rounded, bulbous cavity having a
slightly upwardly tilted orientation. The rounded cavity is
substantially semi-circular with a slightly expanding mouth that
accommodates favorable purchase of a rocker arm described below.
The rounded cavity transitions along an upper section to the planar
upper surface through a curved, finger-like projection, and further
transitions at its lower section to define a lip member that slopes
upwardly away from the lower surface. The lip member has a curved
lower edge that roughly tracks its curved upper edge defining the
cavity, and both the upper edge and the lower edge terminate at a
forward facing leading edge.
[0007] The mount is fixed in the platform so as to remain immobile,
and preferably includes a compressive preload from the platform
above the upper surface so as to embed the mount slightly into the
load board below. In a preferred embodiment, the mount is formed
with an angled back surface that wedges into the platform,
preventing movement of the mount during the testing operation. The
fixed mount functions to receive and act like a fulcrum to a pivot
a second member, i.e. the link.
[0008] The link is formed with an arcuate upper surface that acts
as a contact point that makes connect with the associated contact
pad (or pin) of the IC. The arcuate upper surface has a curvature
that maintains a smooth, rolling contact with the IC's contact pad
as the curved upper surface rotates through its initial stand-by
position through its engaged position. Projecting laterally outward
and away from the arcuate upper surface of the link is a rocker arm
having a neck portion leading to a rounded tip. The rounded tip of
the rocker arm is sized to mate with the cavity in the mount and
provide for a ball and socket type pivoting movement of the link.
That is, the rounded tip of the link when seated in the mount's
cavity, can rotate about the end of the rounded tip as the neck of
the rocker arm swings between the surfaces defining the mouth of
the cavity, i.e., between a stand-by or disengaged position where
the link is not in contact with both the IC and the test device
below, and an engaged position where the link is firmly in contact
with mount and the circuit is complete.
[0009] An elongate, resilient elastomer is positioned behind and
beneath the link member to bias the link member into the stand-by
or disengaged position when no IC is present. The elongate,
resilient elastomer is located in the platform in a cavity shaped
to retain the elastomer. When an IC is brought to bear against the
test socket, the contact pad of the IC pushes the arcuate upper
surface of the link downward against the bias of the elastomer. The
elastomer maintains the rocker arm of the link in contact with the
surface of the mount's cavity. As the force of the downward
movement of the IC chip overcomes the elastomer's bias, the link
will rotate about the mount and the engagement of the rocker arm in
the cavity will be forcefully established by the lateral force of
the tubular resilient member. The mount has a lower surface that is
mated with the electrical contact of the load board or other
fixture, and the link is firmly in contact with the IC contact pad.
Thus, the interconnection of the rocker arm with the mount's socket
completes the circuit between the IC DUT and the associated
fixture.
[0010] The elastomer can be shaped in a square profile, having a
first corner that is rounded in a preferred embodiment. The
elastomer is seated in a wedge-shaped support so that the rounded
corner faces upward and makes contact with the link. The square
shape of the elastomer ensures that the link makes greater contact
with the link as compared with a cylindrical elastomer, which only
makes contact tangentially as opposed to a full face of the square.
The elastomer can only operate in two stages of force by
incorporating a longitudinal hole through the middle of the
elastomer. The hole provides an additional level of force which can
be used to secure the connection and improve the contact while
increasing the range of compliance without sacrificing life of the
elastomer. When the link first makes contact with the elastomer, it
compresses more easily because of the presence of the hole in the
center. Thus, a smaller force is applied to the link. However, once
the compression of the elastomer closes the hole, the full
remaining cross section of the elastomer opposes further
compression, thereby increasing the force on the link. This
increased force ensures greater connection with the device under
test, while not prematurely wearing the elastomer during the
initial contact phase.
[0011] These and many other features of the present invention will
best be understood by reference to the following descriptions and
figures. However, it is to be understood that while the inventor's
best mode has been described and shown, the invention is not to be
limited to any particular drawing or description. Rather, it is
understood that there may be many variations of the present
invention that would be readily appreciated by one of ordinary
skill in the art, and the invention encompasses all such variations
and modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is an elevated, perspective view of an embodiment of
the test socket of the present invention;
[0013] FIG. 2 is an enlarged, elevated cut-away view of a portion
of a test socket illustrating the connector structure; and
[0014] FIG. 3 is an enlarged, cross-sectional view of the link and
mount in the engaged position.
[0015] FIG. 4 is an exploded view of the elastomer and wedge-shaped
support.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] FIG. 1 illustrates an integrated circuit test socket 40 of
the type generally described in U.S. Pat. No. 7,918,669, the
contents of which are incorporated herein. The test socket 40 has a
generally square profile with up to four aligning holes 42 to mount
the test socket on the testing equipment. On a platform 44 of the
test socket 40, a square recess 46 is formed to receive the
integrated circuit chip 14 under test. A plurality of electrical
connectors are formed within the recess 46 as described more fully
in the '669 patent referenced above. Once the chip 14 is placed in
the recess 46, the test socket 40 may be placed, for example, in a
handler work press and clamped in the handler in anticipation of
testing the integrated chip. Other arrangements, both automated and
manual, are also possible with the present invention.
[0017] FIG. 2 illustrates the electrical connectors that cooperate
with the test socket to make the contacts needed to test the DUT.
The test socket 40 sits on a pad 18 as part of the test equipment
that can receive electrical signals from the IC and assess the
quality, strength, and other characteristics of the signal. The
purpose of the test socket 40 is to electrically pass signals from
the contact pad of the chip to the test equipment below via a
plurality of connector assemblies 52 within a platform 12. Each
connector assembly 52 pivots between a stand-by or disengaged
position where no IC is present (as shown in FIG. 3), and an
engaged position, where the engaged position corresponds to the
completed electrical circuit between the IC 14 and the test
equipment pad 18 through the connector assemblies 52. The platform
54 of the socket 40 has a plurality of slots 56 that allow a
portion of the connector 52 to emerge from its upper surface as
shown in FIG. 2. As explained in more detail in U.S. Pat. No.
7,918,669, when the IC chip 14 is placed on the platform 54, the
connectors 79 of the IC chip 14 contact a portion of connector
assembly 52 protruding through the slots 56, and cause the
connector assembly 52 to pivot into the engaged position (FIG. 3).
In this way, the electrical contact is established reliably and
automatically when the IC is placed on the test socket platform
54.
[0018] The connector assembly 52 that establishes an electrical
connection is a two piece assembly having a link member 60 and a
mount element 62. An elongate resilient elastomer 58 is housed in
the platform 54, and serves to bias the connector assembly 52 in
the disengaged position. The mount 62 is retained in the platform
54 and includes a generally planar upper surface and a generally
planar lower surface. In a preferred embodiment, the platform 54 is
sized to compress the mount 62 slightly so that it extends into and
slightly embeds the test equipment contact surface below. Between
the lower and upper surfaces is a laterally opening cavity having a
slightly upwardly tilted orientation. The cavity is substantially
circular up to a mouth, which then gradually widens toward the link
60, and the cavity is approximately sized to retain a portion of
the link member therein. The upper edge of the mouth transitions to
the upper surface through a curved finger-like projection.
Similarly, the lower edge of the mouth transitions to the lower
surface through a projecting lip member. The lip member has a lower
edge that curves upward to a front edge.
[0019] When the IC is brought to bear against the platform 54, the
lower surface of the IC contacts the protruding arcuate surface of
the link 60 and pushes the link down against the bias of the
elongate resilient elastomer 58. This downward force brought to
bear by the IC 14 rotates the link counterclockwise against the
bias of the resilient elastomer 58 (which pushes up on the link),
as the link 60 pivots about the mount 62 via the rocker arm. This
is the engaged position (FIG. 3), as there is a direct flow path
between the contact pad 79 of the IC 14, through the arcuate
contact surface of the link 60 and through the rocker arm to the
mount 62, which is embedded on and affixed to a lead 71 of the load
board/test equipment 18. The flow path being established, signals
can then be processed by the test equipment 18 from the IC 14 in
the conventional manner.
[0020] FIG. 3 illustrates the mounts 62 and link 60 and the
elongate resilient elastomer 58. Each mount 62 includes a generally
planar upper surface 78 and a generally planar lower surface 80,
and in a preferred embodiment the mount includes an angled side
wall 84 that cooperates with a similarly angled surface 86 within
the platform to "trap" or capture the mount in place. This
cooperation between the angled wall and angled surface fixes the
mount in place and reduces any jostling of the mount 60 to
establish a more reliable connection in the connector assembly
52.
[0021] Between the lower and upper surfaces of the mount 60 is a
laterally opening cavity 106 having a slightly upwardly tilted
orientation. The cavity 106 is substantially circular up to a
mouth, which then gradually widens as it opens toward the link 62,
and the cavity 106 is approximately sized to retain a portion of
the link 62 therein. The upper edge of the mouth transitions to the
upper surface 78 through a curved finger-like projection 108.
Similarly, the lower edge of the mouth transitions to the lower
surface 80 through a projecting lip member 110.
[0022] The link 62 has two main components. The first component is
an arcuate contact surface 96 along the upper edge that is shaped
to permit rolling contact with the IC 14 above as the IC applies a
downward force on the link 62, causing the link 62 to pivot about
the mount 60. The second component of the link 62 is a rocker arm
98 having a neck portion that terminates in a bulb-shaped distal
tip. The cavity 106 of the mount 60 and the bulb-shaped distal tip
of the rocker arm 98 are complimentary sized to allow smoothing
pivoting of the rocker arm within the cavity of the mount in a
controlled manner without undue wobble.
[0023] When no chip is present, the resilient member 58 biases the
rocker arm 98 of the link 62 upward through the slot 56 of the
platform 12. This is the disengaged or stand-by position as the
connection assembly 52 is ready for the presence of the IC chip.
When a chip 14 is placed on the platform, the link 62 rotates
downward and contact is made between the chip's electrical contacts
79 and the link 62, which completes a circuit with the mount 60,
contact pad 71, and the testing device 618 to relay the signals
from the chip to the testing device.
[0024] The elongate resilient elastomer 58 is substantially square
with a rounded upper surface 205 arcing across an upper half of the
member from a midpoint of one side 206 to a midpoint of the
opposite side 208. The elastomer 58 sits in a wedge-shaped support
210 with the rounded upper surface 205 exposed to the link 62,
adjacent the mount 60. In a preferred embodiment, the elastomer 58
includes a longitudinal channel or hole 212 that establishes a void
in the elastomer 58. This creates a two-stage contraction of the
elastomer 58 when compressed by the connector assembly 52. In the
initial stage, the elastomer will collapse more easily due to the
presence of the void 212, and the link will be biased with less
force than a solid elastomer. However, as the link continues to
squeeze the elastomer, the void will be reduced until it is
eliminated, whereupon further compression requires greater force to
collapse the elastomer. This two stage compression, where a first
phase compresses the elastomer when a void is still in place, and a
second phase where the void is no longer present or effective in
reducing the compression response, extends the life of the
elastomer by preventing undue wear and strain during the initial
phase of the biasing.
[0025] It will be understood that this disclosure is merely
illustrative, and that it is to be further understood that changes
may be made in the details, particularly in matters of shape, size,
material, and arrangement of parts without exceeding the scope of
the invention. Accordingly, the scope of the invention is as
defined in the language of the appended claims, and is not limited
in any manner by the aforementioned descriptions and drawings.
* * * * *